Title :
MBE synthesis of YBa/sub 2/Cu/sub 3/O/sub y/ superconducting thin films
Author :
Matijasevic, V.C. ; Appelboom, H.M. ; Mathu, F. ; Hadley, P. ; van der Marel, D. ; Mooij, J.E.
Author_Institution :
Delft Univ. of Technol., Netherlands
fDate :
3/1/1993 12:00:00 AM
Abstract :
Issues concerning molecular beam epitaxy (MBE) of the superconductor YBa/sub 2/Cu/sub 3/O/sub y/ are discussed. Films have been prepared by MBE at low pressures using molecular oxygen and ozone. A minimum incidence rate of each of these species for synthesis of YBa/sub 2/Cu/sub 3/O/sub y/ is established and compared with the thermodynamic stability data and lower kinetic limits. For ozone, the lower limit appears to be determined by the growth rate. The best films that are made at low pressures (less than 10/sup -2/ mbar of oxygen or with ozone) have, in general, slightly lower transition temperatures and expanded c-axes, but still sharp transitions and high critical currents. Cation disorder is suggested as a likely explanation for these properties. The model for solubility of Ba on the Y sites is discussed and found to be consistent with experimental results.<>
Keywords :
barium compounds; critical currents; high-temperature superconductors; molecular beam epitaxial growth; solid solubility; superconducting epitaxial layers; superconducting transition temperature; yttrium compounds; 10/sup -2/ mbar; HTSC; MBE synthesis; O/sub 2/; O/sub 3/; YBa/sub 2/Cu/sub 3/O/sub y/ superconducting thin films; cation disorder; expanded c-axes; growth rate; high critical currents; low pressures; molecular beam epitaxy; solubility; transition temperatures; Composite materials; Control systems; Crystalline materials; Feedback; III-V semiconductor materials; Mass spectroscopy; Molecular beam epitaxial growth; Superconducting materials; Superconducting thin films; Superconductivity;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
